Say it: die-NON-ih-kus · Name means: “Terrible claw”
Key facts about Deinonychus
⏳ Lived
115–108 million years ago Early Cretaceous
🥩 Diet
Carnivore (meat-eater)
📏 Length
3–3.4 m (10–11 ft)
↕️ Height
0.8–1 m (3 ft)
⚖️ Weight
60–100 kg (130–220 lb)
📍 Found in
North America
🔎 Discovered
1964 by John Ostrom and Grant Meyer
About Deinonychus
Deinonychus was a feathered hunter about as long as a car, with a huge hooked claw on each foot. It helped scientists realise dinosaurs were active and bird-like.
Deinonychus antirrhopus was a mid-sized dromaeosaurid from the Early Cretaceous of North America. John Ostrom's 1969 description of its agile, bird-like skeleton sparked the 'Dinosaur Renaissance', which reshaped dinosaurs from sluggish reptiles into active animals closely related to birds.
Drawn to scale next to a 1.7 m adult and a 12 m school bus.
Did you know?
Deinonychus's foot claw was about as long as your hand.
It was the real-life size of the 'raptors' in famous dinosaur movies.
Discovering Deinonychus helped scientists see that birds are living dinosaurs.
It probably had feathers all over its body, like a giant, toothy bird.
John Ostrom and Grant Meyer collected the first good specimens in Montana in 1964; Ostrom's 1969 description argued it was warm-blooded and agile, kick-starting the Dinosaur Renaissance.
Several Deinonychus have been found with the remains of the large plant-eater Tenontosaurus, which was once taken as evidence of cooperative pack hunting.
A 2020 study of tooth chemistry found that juveniles and adults ate different food, which fits better with loose groups or mobbing, like Komodo dragons or birds, than with wolf-like packs where everyone shares.
Studies of the sickle claw suggest it was used to grip and pin prey, like the talons of an eagle, rather than slash open victims.
Barnum Brown had found Deinonychus bones as early as 1931 but never formally named them.
DinoVerse· Deinonychus fact sheet
Theropods
🥩 What did it eat?
Food: Tenontosaurus, Zephyrosaurus, small mammals, turtles.
Leapt onto prey and gripped it with its feet, using the large sickle claw on each second toe to pin it down while tearing off flesh with curved, serrated teeth.
Clues scientists use: Deinonychus teeth and skeletons found with Tenontosaurus remains; bite marks on Tenontosaurus bones; hooked serrated teeth and grasping claws; tooth chemistry showing what young and adults ate.
Who might have hunted it: Acrocanthosaurus.
🗺️ Where fossils were found
Cloverly Formation, Montana, USA (North America)
Cloverly Formation, Wyoming, USA (North America)
Antlers Formation, Oklahoma, USA (North America)
Skeleton / museum mount of Deinonychus: Deinonychus skeletal mount on display at the Field Museum of Natural…
Myth or fact?
✗ Myth: Deinonychus used its sickle claw to slice prey open like a knife.
✓ Fact: The claw's shape and tests with model claws suggest it punctured and gripped rather than sliced, holding prey down while the jaws did the work.
✏️ Quick quiz
Circle the right answer. Name: ______________________
What does 'Deinonychus' mean?
A Terrible claw
B Swift thief
C Egg thief
D Running lizard
Which plant-eater has often been found with Deinonychus fossils?
A Stegosaurus
B Triceratops
C Tenontosaurus
D Brachiosaurus
What did discovering Deinonychus help scientists understand?
A Dinosaurs lived in the sea
B Birds are living dinosaurs
C Dinosaurs had fur
D Dinosaurs lived with humans
Answers: 1–A 2–C 3–B
Sources and picture credits
Natural History Museum London — Deinonychus — www.nhm.ac.uk/discover/dino-directory/deinonychus.html
Wikipedia — Deinonychus — en.wikipedia.org/wiki/Deinonychus
DinoVerse · Dinosaur fact sheet
